Quick-connect fittings are employed in many fluid system applications, such as in automotive power steering and brake fluid applications. Many current automotive applications require use of an aluminum alloy fluid conduit having an external coating or cover of nylon or other plastic material. One such tubing is currently marketed under the trademark HYCOT. There is therefore a need in the art for a quick-connect assembly and method of manufacture in which plastic-coated tubing of this character can be rapidly and economically secured to the connector fitting without damaging the plastic coating. A general object of the present invention is to provide a method of manufacturing such a quick-connect, and the resulting product. Another and more specific object of the present invention is to provide such a quick-connect assembly and method of manufacture in which the plastic-coated tubing is securely fastened to the fitting so as to meet or exceed applicable pull force specifications. Another object of the invention is to provide a quick-connect assembly and method of the described character that reliably seals against fluid leakage.
A quick-connect assembly in accordance with the present invention includes a hollow tubular fitting having axially spaced ends and an outer surface with at least one circumferential groove or channel. A tubular conduit of plastic-coated electrically conductive composition is received over one end of the fitting, and is magnetically deformed so as to extend into the channel on the fitting adjacent to the fitting end for fastening the conduit to the fitting. A coupling is rotatably mounted on the opposing end of the fitting for fastening the fitting to a mating coupling, and carries an elastomeric seal in sliding engagement with the conduit or the fitting for preventing leakage of fluid through the assembly.
In the preferred embodiments of the invention, the fitting has three axially spaced channels, with the tubular conduit being magnetically deformed into two of these channels adjacent to one end of the fitting, and with the channel at the opposing end of the fitting cooperating with a radially aligned channel on the coupling for receiving a lock ring to fasten the coupling to the fitting. The middle channel on the fitting has a sloping surface against which the end of the conduit is magnetically formed so that the outer edge of the conduit end is disposed at substantially the adjacent surface of the fitting. In this way, the elastomeric seal carried by the coupling may be slid over the fitting and over the edge of the conduit without being rolled or abraded by the end of the conduit. The sloping surface of the conduit also acts to compress the seal uniformly.
A method of manufacturing a quick-connect assembly in accordance with the present invention thus includes the step of providing a hollow tubular fitting having an outer surface with at least one and preferably a plurality of spaced circumferential channels. A plastic-coated tube of electrically conductive composition such as aluminum alloy is fitted over one end of the fitting so as to encircle one or more of the channels in the fitting. The tube is then magnetically deformed into the underlying channels so as to fasten the tube to the fitting without damaging the plastic coating on the tube. A coupling is then mounted on the fitting in such a way that the coupling is freely rotatable with respect to the fitting and in sealing engagement with the fitting or, more preferably, with the outer surface of the plastic-coated tube.